Metallography is undoubtedly one of the most useful techniques for addressing the numerous questions posed by archaeologists about metal artifacts. The most frequent questions include:

∎ What is the nature of the metal or alloy which the object is made of?

∎ Where did the object and/or its raw materials originate?

∎ What technologies were employed in producing the object?

∎ How old is it?

Many aspects of a metal artifact's history are imprinted in its microstructure (i.e., the structure of the material as revealed under the microscope after appropriate surface preparation). The artifact has a story to tell and the role of the archaeometallurgist is to read and translate the story by studying and interpreting the microstructure. In most cases it is productive to supplement the information obtained from optical microscopy by using other analytical techniques. This will be illustrated below.

Although it is frequently not possible to obtain definitive answers to the above questions, this does not necessarily mean that the analysis has served no useful purpose. For example, it may be just as important to demonstrate what an artifact is not as to prove what it is. Eliminating some of the possible identifications may be a valuable contribution.

Consider the first question: What material is the artifact made of? It is normally essential to perform elemental analyses in order to identify the material. Nevertheless, metallography is a useful first step in answering this particular question. Furthermore, the specimen prepared for optical microscopy can be used without further preparation for other analytical techniques (such as electron probe microanalysis) which can yield an elemental analysis. As will be demonstrated in the following case studies, metallography is of great value in assessing the forms of impurities in metallic materials. This is highly useful information which elemental analysis cannot provide.